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Dr Paul Manning has been fascinated by cruciate ligaments in dogs ever since he was an undergraduate and taught by the late Col John Hickman at Cambridge in 1978/79.  He has developed considerable experience in the use of a traditional technique invented by Paatsama in 1952 and modified subsequently.  Paul has studied the technique and the outcomes over many years, and achieves consistently good results with a 96% success rate as judged by the dogs returning to normal limb function after the surgical repair.  The results have been seen in many different breeds of dog, many different weights of dog from 4kg up to 65kg, and many different ages of dog from 6months to 14 years old.

Dr Manning is very willing and interested to speak to other vets about cruciate problems, and does take referrals for surgery on a strictly ethical basis, whereupon the case is referred back to the client's usual practice after the surgery and initial aftercare is completed.

To discuss or refer a case, please telephone Dr Manning on 01908 611637.

Cruciate Ligament Surgery : Analysing the results 

A case-series of 100 cases of the replacement of ruptured cruciate ligaments using whole thickness skin grafts over a 15 year period

KEYWORDS : canine, cruciate, surgery, graft, follow-up.

Paul R. Manning, MA, VetMB, MSc(VetGP), DProf, MRCVS.,
Astonlee Veterinary Surgery,
Tickford Street
Newport Pagnell
Buckinghamshire MK16 9BA

Mark A. Holmes, MA, VetMB, PhD, MRCVS.
Department of Veterinary Medicine
University of Cambridge,
Madingley Road,
Cambridge.
CB3 0ES

Summary

OBJECTIVES : The use of full thickness skin grafts was the treatment of choice for the surgical treatment of cranial cruciate ligament (CCL) repair during the period from 1960-1970, using the two bone tunnel technique devised by Paatsama in 1952.  The technique was found to be successful, but was very largely abandoned in favour of other techniques, the success of which there was little evidence to indicated that they were more successful than the earlier skin graft technique.  This study describes a case-series of 100 cases of the replacement of ruptured cruciate ligaments using whole thickness skin grafts over a 15 year period.
METHODS : This was a retrospective descriptive study of the use of a single technique of cruciate surgery over a 15 year period.
RESULTS : This paper shows that the use of a skin graft was effective in both eliminating (or substantially reducing) the anterior drawer in achieving stifle joint stability, and restoring normal limb gait in a large variety of breeds, ages and bodyweights of dog for follow up periods of up to 10 years.
CLINICAL SIGNIFICANCE : The results from this study indicate that the use of this technique is capable of generating a high success rate.
 
Introduction

The technique of repair of ruptured cranial cruciate ligaments (CCLs) using fascia lata was first documented by Paatsama in 1952. Vaughan (1963) published the results of a study into the use of different graft materials in which he compared their merits and strengths concluding that skin proved to be superior to either fascia or nylon.   Vaughan and Bowden in 1966 published the results of 30 cases of cruciate repair using a full thickness skin prosthesis, in which 28 cases were judged as 'successful' 1 year following surgery. This judgement was based on the absence of sepsis, and a return to ‘normal’ function with a ‘virtually full range of joint movement.’  Until the late 1960s and early 1970s, the two bone tunnel (Paatsama, 1952) technique for cranial cruciate repair in the dog, using a full thickness skin graft was widely used. Since that time there appears to have been a steady decline in its use.
  
At the time of writing, there are a variety of surgical techniques used as a therapeutic intervention following rupture of the cranial cruciate ligament; these may be categorised as tibial plateau levelling operations (TPLO), extracapsular suture stabilization, fibular head transposition, and intracapsular ligament replacement. A systematic review of the literature comparing the outcomes after the use of these techniques was performed by Aragon and Budsberg (2005).  This review concluded that the literature did not provide sufficient evidence favouring any one surgical technique for the management of canine CCL injury. 

This paper describes a series of 100 cases of canine cranial cruciate rupture in which repair using a full-thickness skin prosthesis was performed by a single surgeon at a single veterinary practice from January 1988 to February 2003. 

Materials and Methods

Recruitment and case definition

The dogs were all seen at a single small animal practice over a period of 15 years. All dogs with a diagnosis of CCL rupture that received surgical treatment were considered for inclusion, a total of 100 cases (86 dogs). Each animal’s age, breed, sex and bodyweight was recorded. Dogs with a diagnosis of bilateral CCL were considered for analysis as two cases, with completion of the follow-up assessment of the results of the first surgery before surgery on the contralateral limb was performed. Fourteen of the dogs included in this study received treatment for bilateral CCL.

 Diagnosis of rupture of the CCL in all cases was made by:

1. Clinical evaluation of the lameness including a walk and trot in the surgery.
2. The presence of anterior drawer (confirmed by examination under general anaesthetic at the time of surgery, as described by Jerram and Walker, 2003) i.e. the movement created when moving the anterior tibia forwards against the distal femur on examination.
3. Visual confirmation of the rupture using stifle arthrotomy.

Two cases were excluded from this case series due to the diagnosis of concurrent disease subsequent to surgery during the follow-up period (one case of osteosarcoma of the femur and one case of osteoarthritis of the hip joint).

Treatment Protocol
Following diagnosis, some owners were advised to reduce the weight of the dog before surgery in cases of clear obesity.  Unless weight loss was required surgery was performed between 3 days and 3 weeks following diagnosis.

Surgical Procedure
Surgery was performed using the techniques described by Paatsama (1952), modified by Vaughan (1966) with refinements as described by Hickman and others (1995). 

The joint was assessed for the presence of anterior drawer following surgery while the dog was still anaesthetised.

Clients were advised to strictly control the dog’s exercise for 3 months following surgery (lead exercise only, avoidance of walking on stairs, and no jumping). Controlled walking was encouraged.

Post-operative assessment
The dogs were re-examined 7-14 days after surgery, at 1 month, and then at monthly intervals for a further 2 months. Subsequent assessments were made at 6 months, 12 months, and at varying intervals of time 2-13 years after surgery wherever possible.  It was not possible to reassess all cases more than 1 month after surgery due to failures of client compliance.
 
A general clinical examination was performed to include an assessment of muscle condition and general health. During each examination the condition of the stifle joint was determined; signs of bone enlargement, crepitus, pain and swelling adjacent to the stifle were recorded. The extent of anterior drawer movement was graded as either absent (no movement discernable), slight (a movement of approximately 1mm or less), or significant (1mm or greater). The gait was assessed and recorded as either ‘normal’ or ‘abnormal’ as judged subjectively by both the clients and the surgeon. The degree of lameness was assessed according to the criteria used by Ballagas (2004). Dogs were assigned a lameness score between 0 and 4 using the clinical assessments described in table 1. Dogs were described as having achieved a 'return to normal limb function' if no lameness was detected and their gait was normal.

Results

Of the 100 operations performed 96 achieved a ‘return to normal limb function’. Two of the repairs failed and two resulted in a final outcome of slight lameness. The results broken down by breed are summarised in table 2. The mean and median values for the follow-up period were 2 years and 3 years respectively. A summary of the follow-up periods tabulated according to age at time of operation and giving mean body weights is provided in table 3.

Discussion

Moore and Read (1995) describe a success rate of 91% resulting in an ‘excellent’, ‘good’ or ‘fair’ outcome based on 11 intra-capsular repairs in a retrospective study comparing intra-capsular repairs with extra-capsular repairs and fibial head transplants; however, this paper described an ‘excellent’ outcome in only 3 of the 11 cases. A study employing force plate technology to provide an objective method of post operative assessment (Conzemius and others, 2005) described a success rate where there was a ‘substantial clinical improvement’ in only 15% of dogs that received an intra-capsular repair (as compared to 40% receiving a lateral suture stabilisation, and 34% receiving TPLO; the force plate analyses suggested that ‘normality’ as defined by objective measurement was achieved in an even smaller proportion of cases. The success rate of 96% described in this case series is greater than that described in previous studies of intra-capsular repairs following CCL rupture. However, the surgical techniques included in intra-capsular repairs, and the methods of assessment and analysis used in the different studies are not necessarily directly comparable.

In a case series there are considerable opportunities for the introduction of bias. It should be acknowledged that the unblinded assessment of outcomes when performed by the surgeon is a concern. Readers should be aware of this unavoidable aspect of the retrospective case series. Another potential source of bias is to include only those cases which had a favourable outcome. Strenuous efforts were made to ensure that data was included for all cases presented for surgery other than the two animals for which concurrent disease was diagnosed at or shortly after surgery. A third source of bias is where patients are followed up for an insufficient period. In clinical practice using a general population it is impossible to achieve a long follow up period for all cases. In this study the range of follow up periods was 1 month to 10 years with a modal value of 2-5 years for all cases which compares favourably with other studies (Innes and others, 2000).

The surgeon believes there were some important technical details about the surgical technique that could contribute to the success of the treatment. It was felt that closure of the joint capsule prior to suturing the distal end of the prosthesis gave a more secure tension on the skin graft.  Consistent suturing of the skin graft so that the ends were parallel to each other helps to reduce the risk of patella luxation post operatively. The precise point chosen for the proximal hole was in the centre of the intercondylar groove/notch at the level of the origin of the CCL.  Miller (1964) described the origin of the CCL as being on the medial aspect of the lateral distal femoral condyle. 
One of the features of the technique used in this study was that the menisci were not attended to as compared to other reports in which the menisci were treated directly during the surgical intervention; eg: Bennett and May (1991), Dupuis and Harari (1993), Moses (2002), Innes (2000).

 The incidence of contralateral CCL rupture at the time of the surgery or following the surgery was approximately 10% of the cases in this series (in which 3 of the 86 dogs were found to require bilateral surgery on first presentation), which was lower than had been reported by Doverspike (1993) who reported that 42 of 114 (37%) dogs ruptured the contralateral CCL after initial diagnosis of unilateral CCL with a mean interval of 17 months after initial surgery. Another study found the incidence of rupture of the contralateral CCL was between 20 and 60% with a mean interval of 14 months. (Moore and Read  1995). Additional findings in this series are comparable with observations from other reports: The dogs that suffered contralateral CCL rupture were mostly over 20kg, with 9 of the 14 dogs weighing 20kg or over at the time of the first operation, (mean 27.5kg), and the average interval from first to second operation (18.5 months in this series compared to 17 months (Doverspike, 1993).

There appeared to be some correlation between size of the breed and the speed of recovery to zero lameness (Table 2).  The median and mean times for the Rottweiller were both 6 months, compared to the smaller West Highland Terrier and Cairn group with a median and mean both of 3 months. Age did not appear to affect the recovery times of the dogs (Table 3).

Conclusions

Successful outcome was achieved in 96 of the 100 cases in this study. 
The potential for a successful outcome following use of the Paatsama technique employing a skin prosthesis has been well demonstrated by this study. It demonstrates that the technique was successful in the author's hands.

Acknowledgements

The late Col John Hickman as Director of Clinical Studies at Cambridge Veterinary School, UK, 1978. Personal communication.
Prof Leslie Vaughan, RVC, for some helpful communications.
Staff and colleagues at Astonlee Veterinary Surgery who have provided excellent support and encouragement to continue the work, and have observed some of the results, helping to confirm opinions.
The Society of Practising Veterinary Surgeons Masters Group for their encouragement and support.
 
References

Aragon, C.L., Budsberg, S.C. (2005) Applications of Evidence-Based Medicine : Cranial Cruciate Ligament Injury Repair in the Dog.  Veterinary Surgery 34, 93-98
Ballagas, A.J., Montgomery, R.D., Henderson, R.A., Gillette, R. (2004) Pre and postoperative force plate analysis of dogs with experimentally transacted cranial  cruciate ligaments treated using tibial plateau levelling osteotomy. Vet Surg. 33, (2) 187-190
Bennett, D., May, C. (1991) Meniscal damage associated with cruciate disease in the dog. Journal of Small Animal Practice 32, 111-117
Conzemius, M.G., Evans, R.B., Besancon, M.F., Gordon, W.J., Horstman, C.L., Hoefle, W.D., Nieves, M.A., Wagner, S.D. (2005) Effect of surgical technique on limb function after surgery for rupture of the cranial cruciate ligament in dogs.  Journal of the American Veterinary Medical Association 226 (2), 232-236
Doverspike,M., Vasseur,P.B., Harb, M.F., Walls, C.M. (1993) Contralateral cranial cruciate ligament rupture : incidence in 114 dogs. J. A.. Anim. Hosp Assoc 29, 167-170
Dupuis,J., Harari,J. (1993)  Cruciate ligament and meniscal injuries in dogs.  Compendium of Continuing Education for the Practising Veterinarian 15, 215-232
Hickman, J., Houlton, J.E.F., and Edwards, B. (1995) Canine cruciate ligament in : An Atlas of Veterinary Surgery.  3rd edtn. Blackwell Science. (Pages 222-225)
Innes, J.F., Bacon, D., Lynch, C., Pollard, A. (2000). Long term outcome of surgery for dogs with cranial cruciate ligament deficiency Vet Rec 147 (12), 325-328
Jerram,R.M, Walker,A.M. (2003) Cranial cruciate ligament injury in the dog:pathophysiology,diagnosis and  treatment. New Zealand Vet J 51(4) 149-158
Miller ,M.E. (1964) Anatomy of the Dog. W.B.Saunders.
Moore, K.W.,  Read, R.A. (1995) Cranial cruciate ligament rupture in the dog - a retrospective study comparing surgical techniques. Australian Vet Journal 72, 281-285
Moses, P.A. (2002) Technique for the surgical repair of caudal peripheral detachment and longitudinal peripheral tears of the medial meniscus in dogs. Veterinary and Comparative Orthopaedics & Traumatology 15, 92-96
Paatsama, S. (1952) Ligament Injuries in the Canine Stifle joint. MSc thesis, Helsinki University, Finland.
Vaughan, L.C. (1963) A study of the replacement of the anterior cruciate ligament in the dog by fascia, skin and nylon. Veterinary Record 75, 537-541
Vaughan, L.C. and Bowden,N.L.R.(1966) The use of skin for the replacement of the anterior cruciate ligament in the dog : A review of 30 cases. Journal of Small Animal Practice 5, 167-171

Table and figure legends:

Lameness score	Interpretation
0	Absent.
1	Minor gait abnormality with constant weight bearing
2	Obvious gait abnormality with constant weight bearing.
3	Intermittent non-weight bearing.
4	Non-weight bearing.

Table 1: Lameness scoring system used in the post-operative assessment of dogs as originally described by Ballagas (2004).

 

Breed	Nos	RH	LH	Median time (in months) to recover to 0 lameness. (Mean in brackets)	Nos failed	Min time (in months)	Max time (in months)	Male	Female	Inc bilateral	Median follow up time (Mean in brackets)	Range of follow up times
Rottweiller	9	5	4	6 (6)		4	6	2	7	1	2years (2.1yrs)	0.75-3yrs
Westies and Cairns	4	3	1	3 (3)		3	3	1	3	0	3yrs (2.25yrs)	0.25-3yrs
Springer Spaniels	3	1	2	3 (1.7)		1	3	2	1	0	1yr (1yr)	1-1yr
Boxer	8	3	5	3 (3.6)		1	6	5	3	2	3yrs (3.9yrs)	2-7yrs
Border Collie	3	1	2	2 (2)		1	3	1	2	1	3yrs (2.7yrs)	2-3yrs
Bernese Mountain Dog	1	0	1	3 (3)		3	3	0	1	0	5yrs (5yrs)	5yrs
Great Dane	1 (became bilateral after end of study period)	1	0	2.5 (2.5)		2	3	1	0	1(became bilateral after end of study period)	0.25yr (0.25yr) (Subsequent to period of study, follow up was 4years and zero lame for the whole period)	2-3months
Yorkshire Terrier	4	1	3	2 (1.7)	1	1	3	1	3	0	0.5yr (0.56yr)	1 dog failure =lameness score 4 2mth-1year
Cross breeds	28	13	15	2 (2.5)		1	3	14	14	4	3yrs (2.79yrs)	1mth-7yrs
Labrador	7	4	3	2 (2.4)	1	1	3	5	2	2	6yrs (3.79yrs) 1 dog (severely obese) failure=lameness score 4	2mths-8yrs
Cocker Spaniel	2	2	0	2 (2)	1	1	3	1	1	0	3.5yrs (3.5yrs) 1 dog outcome=lameness score 1	3yrs-4yrs
Min Poodle	1	0	1	failed	1	Outcome=lameness score 1	Outcome=lameness score 1	1	0	0	2yrs (2yrs) 1 dog 14 years old at time of operation	2yrs
Staffordshire Bull Terrier	3	1	2	3 (3)		3	3	3	0	1	2yrs (2.33yrs)	1yr-3yrs
GSD	4	3	1	3 (2.1)		0.5	3	1	3	0	4yrs (3.33yrs)	1.5-5yrs
Bichon Freis	3	3	0	3 (3)		3	3	0	3	0	0.5 yr (1.25yrs)	2mths-3yrs
Tibetan Terrier	2	1	1	2.5 (2.5)		2	3	2	0	1	0.6yr (0.6yr)	2mths-1yr
Jack Russell Terrier	6	4	2	3 (2.8)		2	3	1	5	0	2yrs (2.35yrs)	1mth-6yrs
Bull Mastiff	2	2	0	2.5 (2.5)		2	3	0	2	0	1yr (1yr)	2yrs
German Spitz	1	0	1	1 (1)		1	1	0	1	0	3yrs (3yrs)	3yrs
Bulldog	1	1	0	3 (3)		3	3	1	0	0	8yrs (8yrs)	8yrs
Cavalier King Charles Spaniel	2	1	1	3 (3)		3	3	2	0	1	1yr (1yr)	1yr
Retriever	4	2	2	3 (3)		3	3	1	3	1	8yrs (6yrs)	2yrs-10yrs
Belgian Shepherd	1	1	0	3 (3)		3	3	1	0	0	3yrs (3yrs)	3yrs
Total	100	53	47	3 (2.93)	4	0.5	6	45	55	14	3yrs (2.84 yrs)	1month to 10years

Table 2: Summary of results and follow up times of dogs treated with cranial cruciate repair surgery showing the breed distribution. Breed and sex distribution. (Median = where n=2r+1, median = the (r+1)th observation. If n is an even number 2s, median= ½ way between the sth and (s+1)th observations. If s and (s+1) are the same number, that is the median. Mean= sample mean = Ex/n.)

One English Setter was removed from the study due to concurrent osteoarthritis of the hip. This case does not appear in the tables.

Footnote.

There has been quite a lot of anecdotal discussion about what happens to the skin grafts over time, but little evidence to explore the facts.  One labrador who had skin grafts placed in both stifles to replace ruptured cruciate ligaments at about 7 and 8 years old had to be euthanased at 15 yearsold due to old age, and his owner was very keen to particpate in any way she could to help other dogs and to help vets learn from what for her and her dog was an experience of excellent and long lasting recovery from the two cruciate operations.  A post mortem was carried out, and the joints examined in detail by an independent histopathologist whose report is attached below this selction of the slides.  This shows that the skin grafts were still in place, had collagenized in the joint, and were still attached 7 and 8 years after the operations.